Lists, unlike strings, are mutable. We can use that to modify their data with indexes.
There is a list planets with the names of the Solar system planets. However, instead of the 5th planet, there's an X. Replace it with the real name of the 5th planet (it's Jupiter). Do not forget, the first letter must be a capital one! Your program shouldn't print anything.
Note that the list planets has already been defined, you just need to change one element. Mind its index!
